If you pluck that out it completely freezes 50%+ of their operations, people really don't get how much stuff in modern companies is reliant on MS stuff (and thus why they are one of the richest companies on the globe)
Moving away from that would be a massive change management undertaking, but it's not the "Office" part which is our primary challenge. To be fair, I'm not sure we could actually survive the change management required to leave the Office and Windows part, as it would be completely unfamiliar territory for like 95% of our employees, but the collective we at least think that we can. We have quite a lot of Business Central 365 instances, the realistic alternative to those would be Excel (but not Excel). SharePoint is also a semi-massive part of our business as it's basically our "Document Warehouse".
I guess maybe I'm using the 365 term wrong?
You're not missing anything, but that's our current exit strategy none the less. We need to be capable of exiting Microsoft within a month if required. It even says Excel in our strategy even though it would obviously need to be a different spreadsheet program. Well, maybe we would be allowed to use non-cloud Excel, I'm not too sure about that actually. I'm only involved in these things from SWE side of things where I have to give them a strategy for our part, which is very easy because everything is containerized and almost non-platform dependent, so it would be relatively easy to migrate away from Azure. The biggest challenge for our part of the business would be our reliance on AD (well Entra ID) authentication flows. Not a big challenge as far as the actual auth flows, because we could easily accept tokens from something like Keycloak but it would be a challenge to migrate the AD for the SysOps guys.